Chromatography apparatus

ABSTRACT

An apparatus for use in liquid chromatography involves a column filled with media bounded axially by at least one porous member. The column has an inlet end with an inflow region between the inlet and a porous member. The inflow region may be sufficiently long so that a chromatography sample module may be disposed therein. The column may be sufficiently long so that a chromatography sample module may be disposed therein. The column may also have an outlet end with an outflow region between the outlet end and a second porous member. The inflow region may be substantially longer than the outflow region. The porous members may be moveable relative to the column.

This application is a continuation-in-part of U.S. patent Ser. No.09/137,019 filed Aug. 20, 1998, now U.S. Pat. No. 6,132,605 (which is acontinuation-in-part of U.S. patent Ser. No. 08/968,287 filed Nov. 12,1997, now U.S. Pat. No. 6,086,766) and a continuation-in-part of U.S.Pat. Ser. No. 09/548,261 filed Apr. 12, 2000, now U.S. Pat. No.6,294,087 (which is a divisional application of U.S. patent Ser. No.09/137,278 filed Aug. 20, 1998, now U.S. Pat. No. 6,139,733), and acontinuation-in-part of U.S. patent Ser. No. 09/548,214 filed Apr. 12,2000, now U.S. Pat. No. 6,221,252 (which is a divisional application ofU.S. patent Ser. No. 09/137,278 filed Aug. 20, 1998, now U.S. Pat. No.6,139,733). This application claims priority from each of theabove-referenced applications.

BACKGROUND OF THE INVENTION

In one aspect, the invention relates to columns used in liquidchromatography. In another aspect, the invention relates to introducinga sample into a chromatography column. The invention, in yet anotheraspect, relates to an apparatus and method for sealing the openings ofvessels; in particular, the apparatus relates to sealing the openings ofliquid chromatography cartridges.

Liquid chromatography is a technique for separating the individualcompounds that exist in a subject sample. In employing the technique,the subject sample is carried in a liquid, called a mobile phase. Themobile phase carrying the subject sample is caused to migrate through amedia, called a stationary phase. Different compounds will havediffering rates of migration through the media, which effects theseparation of the components in the subject sample. Liquidchromatography is commonly performed with reusable columns or withdisposable cartridges, both of which are usually cylindrical, in whichthe media bed is bounded axially by porous plates, or plates containingdefined flow paths, through which the mobile phase will flow. (See U.S.Pat. No. 4,250,035 to McDonald et al.)

Chromatography systems demand that a reliable seal be created betweenthe column and the head through which the mobile phase enters. This is aparticular problem in chromatography systems that employ disposablecartridges in which precise tolerances and careful machining that arecustomarily required for the creation of effective seals will increasemanufacturing costs. Methods of sealing liquid chromatography cartridgestypically require forcing a sealing head onto or into the cartridge.Some prior art techniques involve forcing a one-piece sealing head withan elastomeric o-ring, connected radially or to an end of the sealinghead, into the cartridge. Alternately, a tapered sealing head can beforced into a cartridge without employing an o-ring to create a seal.Other prior art techniques employ o-rings or knife-edges (see U.S. Pat.No. 5,601,708 to Leavesley) oriented axially on a sealing head thatcreate seals with the edges of the cartridges at their open ends.

Chromatography columns and cartridges also demand a close contactbetween the sealing heads and the media bed. Prior art sealingtechniques often create gaps between the sealing head and the media bed.Even small gaps can reduce the resolution of distinct components thatcan be achieved. At the entrance of a column or cartridge, gaps betweenthe sealing head and the porous plate or media will allow the subjectsample to disperse and become diluted. At the exit of a column orcartridge, gaps will create a volume in which distinct fractions of thesubject sample, which were separated during migration through the media,can blend back together. Thus, gaps at either end of the media bed candegrade the analytic performance of chromatography columns orcartridges.

When chemists optimize liquid chromatographic separations conditions,they may need to dissolve the sample mixture in a dissolution solventwhich may be nonideal for elution. This can result in poor separationand poor recovery of desired components.

One solution to this problem is to pre-absorb the sample onto a mediaprior to chromatography. This involves dissolving the sample mixture ina suitable solvent and adding an amount of a dry media (usually similarto the media being used for the separation) to this solution. Thedissolution solvent is then evaporated off, usually using a rotaryevaporator, leaving the sample mixture dry, and absorbed to the media.The pre-absorbed media is then placed at the head of a pre-packed glass,metal or plastic chromatography column, and the optimizedchromatographic solvent would flow through the pre-absorbed media andthen through the column of separation media. This method has thepotential hazard of the operator coming into contact with the drypowdery media both before and after the addition of the sample. Thismethod also can lead to poor separations and recovery.

SUMMARY OF THE INVENTION

In one aspect, the invention in general relates to sealing achromatography cartridge containing a media bed that forms a stop. Theapparatus involves a sealing head that includes a first head piece, asecond head piece, and an elastomeric sealing member. The first headpiece includes a first compression face and a contact face adapted tocontact said stop. The second head piece includes a second compressionface and a compression force receiving member. The elastomeric sealingmember is at least partially situated between the first and secondcompression faces. The first head piece, the second head piece, and theelastomeric sealing member are sized to slide easily into achromatography cartridge having interior walls and containing achromatography media bed that is bounded axially by porous plates.

In operation, the sealing head is inserted into the cartridge. Frictionbetween the elastomeric sealing member and the cartridge is minimizedwhen the elastomeric sealing member is in an uncompressed state duringinsertion. After the head has been inserted into the cartridge, theelastomeric sealing member is compressed between the first and secondcompression faces, by moving the second head piece toward the media bedso that the contact face presses against the stop. Compression of theelastomeric sealing member causes the elastomeric sealing member toexpand laterally so that it presses against the interior walls of thecartridge and creates a seal.

The sealing apparatus may be removed from the cartridge by raising thesecond head piece relative to the first head piece, thus reducing thecompression forces on the elastomeric sealing member and lessening itslateral expansion. This reduces the frictional contact between theelastomeric sealing member and the interior walls of the cartridge, sothat the sealing member and the first and second head pieces may be moreeasily removed.

By providing a second sealing apparatus, it is possible to seal bothends of a chromatography cartridge in the manner described above.

In the preferred embodiments, the first head piece contains a bodyportion and an outwardly-extending shoulder. The first compression faceis located on the shoulder. Additionally, the first and second headpieces are shaped and sized so that the second head piece may slidablyreceive the body of the first head piece. The first head piece defines aflow path for the passage of a fluid, such as a mobile phase forchromatography. The contact face on the first head piece includes aslight conical concavity that helps to distribute a mobile phaseuniformly to the media bed.

In operating the preferred embodiments, the contact face of the firsthead piece presses against the porous plate while the elastomericsealing member is compressed axially. This axial compression causes theelastomeric sealing member to expand laterally, thus forming a seal withthe interior walls cartridge.

In another aspect, the invention in general relates to sealingchromatography columns containing a first media bed, by creating aplurality of seals. The apparatus involves a sealing head that includesa first head piece, a second head piece, an intermediate head piece, anda plurality of elastomeric sealing members. The first head piece has abody portion and a shoulder that extends farther radially than the bodyportion. The second head piece and the intermediate head piece definecentral openings through which the body portion of the first head pieceis slidably fitted. The elastomeric sealing members are annular and theycircumscribe the body portion of the first head piece. A firstelastomeric sealing member is between the shoulder and the intermediatehead piece. A second elastomeric sealing member is between the secondhead piece and the intermediate head piece.

The first and second head pieces, the intermediate head piece, and theelastomeric sealing members are sized to slide easily into thechromatography column.

In operation, the apparatus is inserted into the column. Frictionbetween the elastomeric sealing members and the column is minimized whenthe elastomeric sealing members are in an uncompressed state duringinsertion. After the head has been inserted into the column, theelastomeric sealing members are compressed, by moving the first andsecond head pieces relative to each other, so that the second head piecemoves toward the shoulder of the first head piece. The first elastomericsealing member is compressed between the shoulder and the intermediatehead piece. The second elastomeric sealing member is compressed betweenthe intermediate head piece and the second head piece. Compression ofthe elastomeric sealing members causes them to expand laterally so thatthey press against the interior walls of the column and create seals.

In alternate preferred embodiments, an inner cartridge fits into an openend of the column. Preferably, the inner cartridge is a sample module.The sample module contains a subject sample. The sample module may alsocontain chromatography solvents and a chromatography media of either thesame or different composition that is used in the column. The shoulderof the first head piece and the first elastomeric sealing member aresized to fit slidably into the sample module, when the first elastomericsealing member is uncompressed. When a compressive force is applied tothe sealing head, the first elastic sealing member forms a seal with thesample module and the second elastic sealing member forms a seal withthe column.

Embodiments of these aspects of the invention may include one or more ofthe following advantages. Insertion of the sealing apparatus into achromatography cartridge creates minimal friction between the sealinghead and the interior walls of the cartridge. Use of the sealingapparatus does not require close tolerances that create a precise fitbetween the sealing head and the cartridge. A small amount of force isrequired to create a seal with chromatography cartridges, relative toprior art methods. The sealing apparatus can be easily removed from achromatography cartridge, so that the cartridge can be replaced. Becauseuse of the apparatus can minimize frictional shear forces duringinsertion into a chromatography cartridge, wear on elastomeric sealingmembers is reduced. Using the apparatus can create a high quality seal.Using the apparatus can minimize the gap that is created between asealing head and the media bed or porous plate, when sealing achromatography cartridge. Using the apparatus can axially compress themedia bed while sealing a chromatography cartridge. The apparatus hasthe ability to create a seal by the relative motion of two pieces thatcompress an elastomeric sealing member without exerting axial force onthe media itself. The apparatus can also create a seal by pressing thesealing head against a rigid stop within the column. The apparatus canbe adapted for sealing chromatography cartridges having media beds ofvarying lengths and distances from the opening of the cartridge. Theinvention may be used with any type of column, including disposablepre-packed cartridges, columns with flexible walls, and columns made of,e.g., glass, steel, or a synthetic material. By employing a samplemodule that is fitted and sealed within the column a subject sample maybe analyzed with two different media in one column. The sample moduleand the column may employ either porous plates or plates having drilledchannels to bound the media beds. The outwardly extending shoulder mayhave any shape that allows it to exert a compressive force on anelastomeric sealing member.

In an alternative aspect, the invention features, in general, achromatography sample module including a flow-through member having aninlet and an outlet and chromatography media within the flow-throughmember. A sample is added to the media, and the module, with the samplecarried therein, can then be connected to a separation column.

Preferably the chromatography sample module is a tubular member that issized to fit within the end of a chromatography column that is used forseparation of the sample contained on the media in the module.Alternatively, the module can be connected to the chromatographyseparation column by a flow line. The sample in the dissolution solventcan be added to the sample module, and then the dissolution solvent canbe evaporated. Alternatively, the sample in the dissolution solvent canbe added to the sample module as a liquid without evaporation.

In yet another alternative aspect the invention features a rack ofsample modules arranged in an array.

Embodiments of these aspects invention may include one or more of thefollowing advantages. The samples can be easily introduced intoseparation columns. Various solvents can be used for separation anddissolution of the sample, permitting optimization of the separationprocedure. Samples are easily preprocessed, and the operator is notexposed to the media before or after adding the sample. A large numberof samples can be prepared for processing at one time, facilitating thecarrying out of multiple separations at one time.

Other features and advantages of the invention will be apparent from thefollowing description of the preferred embodiments thereof and from theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic cross-sectional view of a sealing apparatusaccording to the invention and a chromatography cartridge.

FIG. 2 is a diagrammatic cross-sectional view of a sealing apparatusaccording to the invention.

FIG. 3 is a diagrammatic cross-sectional view of a sealing apparatusaccording to the invention showing the formation of a seal with achromatography cartridge.

FIG. 4A is a diagrammatic vertical-sectional view of a sealing apparatusaccording to the invention.

FIG. 4B is a diagrammatic vertical-sectional view of a sealing apparatusaccording to the invention and a chromatography column.

FIG. 4C is a diagrammatic vertical-sectional view of a sealing apparatusaccording to the invention showing the formation of seals with achromatography column.

FIG. 5A is a diagrammatic exploded vertical-sectional view of analternate sealing apparatus according to the invention with achromatography column.

FIG. 5B is a diagrammatic vertical-sectional view of an alternatesealing apparatus according to the invention showing the formation of aseal with a chromatography column.

FIG. 6 is a schematic diagram of a chromatography system according tothe invention.

FIG. 7 is a vertical sectional view of a chromatography sample moduleused in the FIG. 6 system.

FIG. 8 is a plan view of a rack containing a plurality of the FIG. 7sample modules in an array.

FIG. 9 is an elevation of the FIG. 8 rack and modules.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-3, there is shown a sealing apparatus employingsealing head 2, which includes first head piece 4, having body 6 withlongitudinal axis 8. First head piece 4 has outwardly-extending shoulder10, first compression face 12 that is located on shoulder 10, andcontact face 14. Part of contact face 14 has a slightly conical shape orother concavity (exaggerated in FIGS. 2 and 3). First head piece 4defines flow path 16 along axis 8. Second head piece 18, which includessecond compression face 20 and a compression force receiving memberextending thereabove, is sized to slidably receive body 6 of first headpiece 4. Elastomeric sealing member 22 is at least partially situatedbetween first compression face 12 and second compression face 20.

Sealing head 2 and its components are sized to fit slidably intocartridge 24, having chamfered edges 26, and chromatography media 28bounded axially by porous plates 30 which form a rigid stop within thecartridge.

The connection of the apparatus is shown in FIGS. 1 and 3. As shown inFIG. 1, first head piece 4, elastomeric sealing member 22, and secondhead piece 18 are oriented so that they may slide into cartridge 24. Asshown in FIG. 3, after first head piece 4, elastomeric sealing member22, and second head piece 18 are situated within cartridge 24, andcontact face 14 is stopped at porous plate 18, additional downward forceon second head piece 18 causes first head piece 4 and second head piece18 to be moved toward each other, thus axially compressing elastomericsealing member 22 between first compression face 12 and secondcompression face 20. The axial compression of elastomeric sealing member22 causes it to expand laterally and press against cartridge 24, thusforming a seal.

As shown in FIG. 3, insertion of sealing head 2 can create a closeconnection between contact face 14 and porous plate 30. Compressingelastomeric sealing member 22 between first compression face 12 andsecond compression face 20, by pressing second head piece 18 againstelastomeric sealing member 22, which in turn presses first head piece 4against porous plate 30, can maintain a close connection between contactface 14 and porous plate 30 while forming a seal between sealing head 2and cartridge 24.

In the preferred combination, sealing head 2 is used to seal cartridge24 having flexible walls. In other combinations, sealing head 2 is partof a containment structure assembly for receiving cartridge 24. Thecontainment structure assembly may be pressurizable, such as a pressurevessel assembly that receives cartridge 24, compresses the flexiblewalls of cartridge 24, and provides uniform packing for chromatographymedia 28 therein. A containment structure of this type is discussed inU.S. Pat. No. 4,250,035 to McDonald, et al., which is incorporatedherein by reference. Another type of pressurizable containment structureis discussed in U.S. Pat. No. 5,601,708 to Leavesley, which is alsoincorporated herein by reference. In other combinations, sealing head 2is used to seal cartridge 24 having rigid walls.

The radial displacement of the outer surface of elastomeric sealingmember 22 accommodates a range of inner diameters of cartridge 24,permitting effective seals while relaxing tolerances for the innerdiameter of cartridge 24 to ±0.005″.

Referring to FIGS. 4A-4C, there is shown an alternate preferredembodiment of a sealing apparatus employing sealing head 210, whichincludes first head piece 212, second head piece 224, intermediate headpiece 228, and first and second annular elastomeric sealing members 234,236.

First head piece 212 has body 214 with longitudinal axis 216. First headpiece 212 has outwardly extending shoulder 218, and contact face 220.Part of contact face 220 has a slightly conical shape or otherconcavity. First head piece 212 defines flow path 222 along axis 216.

Body 214 of first head piece 212 fits slidably through second head piece224, intermediate head piece 228, and through first and secondelastomeric sealing members 234, 236.

First elastomeric sealing member 234 is adjacent to both shoulder 218and intermediate head piece 228. Second elastomeric sealing member 236is adjacent to both intermediate head piece 228 and second head piece224.

Sealing head 210 and its components are sized to fit slidably intocolumn 238, having chamfered edges 240, filled with chromatography mediabed 242, which is bounded axially by porous plates 244, 245.

The connection of the apparatus is shown in FIGS. 4B and 4C. As shown inFIG. 4B, first head piece 212, second head piece 224, intermediate headpiece 228, and elastomeric sealing members 234, 236 are oriented so thatthey may slide into column 238. As shown in FIG. 4C, after sealing head210 is situated within column 224, first head piece 212 and second headpiece 224 are moved relative to each other. This relative movementaxially compresses first elastomeric sealing member 234 between shoulder218 and intermediate head piece 228 and also compresses secondelastomeric sealing member 236 between intermediate head piece 228 andsecond head piece 224. The axial compression of elastomeric sealingmembers 234, 236 causes them to expand laterally and press against theinterior surface of column 238, thus forming seals.

As shown in FIG. 4C, insertion of sealing head 210 can create a closeconnection between contact face 220 and porous plate 244. Compressingelastomeric sealing members 234, 236, by pressing second head piece 224against second elastomeric sealing member 236, which in turn pressessecond elastomeric sealing member 236 against intermediate head piece228, intermediate head piece 228 against first elastomeric sealingmember 234, first elastomeric sealing member against shoulder 218, andcontact face 220 against porous plate 244, can maintain a closeconnection between contact face 220 and porous plate 244 while forming aseal between sealing head 210 and column 238.

Referring to FIG. 6, there is shown chromatography system 310 whichincludes a source of solvent 312, pump 314, sample module 150, liquidchromatography column 138, and sample collection vessel 320. In thissystem, the sample to be analyzed is preabsorbed onto media in samplemodule 150 prior to pumping solvent into module 150 and intochromatography column 138 to perform the separation procedure.

Referring to FIG. 2, it is seen that sample module 150 includescylindrical plastic tube 152, porous plates 156, 157 (made of inertplastic porous frits), and chromatography media 154 (only partiallyshown in the figures) between porous plates 156, 157.

As appears from FIGS. 5A and 5B, sample module 150 is designed to fitwithin chromatography column 138 at the entrance thereof and to besealably connected to the sealing head. Tube 152 is designed to fitwithin column 138 with minimal space between the two; in particular,there is 0.000″ to 0.010″ of radial clearance.

Sample module 150 can be filled with media that is the same as or isdifferent from the media of chromatography column 138. The sample isdissolved in the required solvent and added to the top of sample module150, where it is drawn into the media by capillary action. Thisdissolution solvent is then removed by placing sample module 150 in avacuum chamber. Heat may also be applied.

After sample module 150 has dried, it can be placed directly insideseparation column 138 so that the lower porous plate 157 is an inintimate contact with the surface of the separation media or with aporous plate within the separation column on top of the separationmedia.

Alternatively, sample module 150 can be placed in a remote tubeconnected by a solvent line. Alternatively, the sample can be dissolvedin a separation solvent (or a weaker solvent), and added to module 150.The wet module can then be loaded into the column or into a remote tube.

Examples of the types of complex samples where this technique hasparticularly advantageous use include synthetic organic reactionmixtures and natural product extracts, (e.g., from fermentation brothsor plants). These samples often need to be dissolved in a solvent notcompatible with the optimized separation solvent. Solvents are organizedaccording to their “solvent strength,” where hexanes have a value closeto zero, and methanol has a value of 0.95. Optimized separation eluentsoften have a lower solvent strength; e.g., hexane:ethylacetate 1:1 has asolvent strength of 0.295. If the sample needs to be dissolved in astrong solvent such as methanol, there will be a solvent strengthdifference of 0.655 seen initially after loading the sample onto thecolumn, and this will impair the separation of the sample. If the sampledissolved in methanol is instead preadsorbed to the media in the samplemodule and dried, the sample will not face this impairment duringseparation.

Referring to FIGS. 8 and 9, sample modules 150 can be supplied in racks332, and a whole rack of sample modules 150 can be efficiently preparedat one time rather than one at a time.

FIGS. 5A and 5B show the placement of a module 150 in a column 138 andthe sealing of the module 150 and column 138 to a sealing head used todeliver solvent. Sealing head 110 has first head piece 112, second headpiece 124, intermediate head piece 128, and first and second annularelastomeric sealing members 134, 136.

First head piece 112 has body 114 with longitudinal axis 116. First headpiece 112 has outwardly extending shoulder 118, and contact face 120.Part of contact face 120 has a slightly conical shape or otherconcavity. First head piece 112 defines flow path 122 along axis 116.

Body 114 of first head piece 112 fits slidably through central openingsin second head piece 124, intermediate head piece 128, and first andsecond elastomeric sealing members 134, 136.

Second head piece 124 has outwardly extending compression forcereceiving member 146. Intermediate head piece 128 has narrow portion 148distal from second head piece 124.

First elastomeric sealing member 134 is adjacent to both shoulder 118and narrow portion 148 of intermediate head piece 128. Secondelastomeric sealing member 36 is adjacent to both intermediate headpiece 128 and second head piece 124.

Sample module 150 has tube 152 which contains second chromatographymedia bed 154 bounded axially by second porous plates 156, 157. Theouter diameter of tube 152 is sized so that sample module 150 fits intocolumn 138. The inner diameter of tube 152 is sized so that it mayslidably receive shoulder 118, first elastomeric sealing member 134, andnarrow portion 148 of intermediate head piece 128.

Intermediate head piece 128, second elastomeric sealing member 136, andsecond head piece 124 are sized to fit slidably into column 138, havingchamfered edges 140, filled with first chromatography media bed 142,which is bounded axially by first porous plates 144.

Referring to FIG. 5B seals are formed with the apparatus by insertingsample module 150 into column 138 so that second porous plate 157 abutsfirst porous plate 144. Sealing head 110 is then inserted into column138 and tube 152 of sample module 150, so that shoulder 118, firstelastomeric sealing member 134, and narrow portion 148 are within tube152, and contact face 120 abuts second porous plate 156. Sealing head110 extends far enough into column 138 so that second elastomericsealing member 136 opposes the inner surface of column 138.

Downward compressive force applied to outwardly extending compressionforce receiving member 146 causes second head piece 124 to sliderelative to first head piece 112 and transmits compressive force tosecond elastomeric sealing member 136, intermediate head piece 128,first elastomeric sealing member 134, shoulder 118, second porous plate156, first media bed 154, second porous plate 157, first porous plate144, and first media bed 142. The compressive force causes first andsecond elastomeric sealing members 134, 136 to expand radially so thatfirst elastomeric sealing member 134 forms a seal with tube 152 andsecond elastomeric sealing member 136 forms a seal with column 138.

The seals are released by applying an upward force to second head piece124, thereby reducing the compressive force on the components of sealinghead 110 and reducing the radial expansion of elastomeric sealingmembers 134, 136.

Preferably, cartridge 24 and tube 152 are made of high-densitypolyethylene. However, columns and cartridges may be constructed ofother materials, including glass or stainless steel. Preferably,elastomeric sealing member 22 is made of a fluorocarbon polymer, such asthat sold under the trade name CHEMRAZ.

What is claimed is:
 1. A chromatography column comprising: a tubularmember having an inlet end, an outlet end, an inner surface, and alongitudinal axis; first and second independent porous members disposedwithin said tubular member, said first porous member being spaced fromsaid inlet end so as to define an inflow region within said tubularmember and between said first porous member and said inlet end; a secondporous member disposed within said tubular member, said second porousmember being spaced from said outlet end so as to define an outflowregion within said tubular member and between said second porous memberand said outlet end; and a chromatography media disposed within saidtubular member, said chromatography media being bounded axially betweensaid first and second porous members; wherein said first porous memberis in axially slidable contact, toward said chromatography media, withsaid inner surface of said tubular member.
 2. The chromatography columnof claim 1 wherein said inner surface is sufficiently smooth, near saidfirst porous member, so as to render said first porous member moveablerelative to said tube, when subject to compressive force, so that saidfirst porous member can compress said media.
 3. The chromatographycolumn of claim 2 wherein said inner surface is sufficiently smooth,near said second porous member, so as to render said second porousmember moveable relative to said tube, when subject to compressiveforce, so that said second porous member can compress said media.
 4. Thechromatography column of claim 1 wherein said inner surface issufficiently smooth, near said second porous member, so as to rendersaid second porous member moveable relative to said tube, when subjectto compressive force, so that said second porous member can compresssaid media.
 5. The chromatography column of claim 1 wherein said inflowregion comprises a module receiving region between said first porousmember and said inlet end, said module receiving region beingsufficiently long to receive a sample module entirely within said inflowregion.
 6. The chromatography column of claim 5 wherein said inflowregion further comprises a sealing region between said module receivingregion and said inlet end, said sealing region being sufficiently longto receive a sealing head for making a seal with said inner surface ofsaid tubular member.
 7. The chromatography column of claim 5, furthercomprising a tubular sample module disposed within said module receivingregion, a second media within said sample module, and a chromatographysample carried on said second media, said sample module having a moduleinner surface, a module inlet end and a module outlet end.
 8. Thechromatography column of claim 7 wherein said chromatography sample hadbeen added to said media by: providing said second media prepackedwithin said sample module; dissolving said sample in a solvent; addingsaid solvent and said dissolved sample to said prepacked media; andevaporating said solvent.
 9. The chromatography column of claim 7wherein said chromatography sample module further comprises a modulesealing region, between said second media and said module inlet end,said module sealing region being sufficiently long to receive a modulesealing head for making a seal with said module inner surface.
 10. Thechromatography column of claim 9 further comprising a first sealing headhaving a first elastomeric sealing member for making a seal with saidinner surface at said sealing region.
 11. The chromatography column ofclaim 10 wherein said first sealing head further comprises a secondelastomeric sealing member for making a seal with said module innersurface.
 12. The chromatography column of claim 10 further comprising asecond sealing head having a third elastomeric sealing member for makinga seal with said inner surface at said outflow region.
 13. Thechromatography column of claim 1 wherein said outflow region is sized toreceive a sealing head for making a seal with said inner surface of saidtubular member.
 14. The chromatography column of claim 1 wherein saidinner surface of said tubular member is substantially cylindrical. 15.The chromatography column of claim 1 wherein said inner surface of saidtubular member is substantially cylindrical throughout said inflowregion.
 16. The chromatography column of claim 1 wherein said innersurface of said tubular member is substantially cylindrical throughoutsaid outflow region.
 17. The chromatography column of claim 1 whereinsaid tubular member further comprises a first chamfered region near saidinlet end.
 18. The chromatography column of claim 17 wherein saidtubular member further comprises a second chamfered region near saidoutlet end.
 19. The chromatography column of claim 1 wherein saidtubular member further comprises a second chamfered region near saidoutlet end.
 20. The chromatography column of claim 1 wherein saidtubular member is made of a flexible material capable of radialcompression.
 21. The chromatography column of claim 1 wherein saidtubular member comprises polyethylene.
 22. The chromatography column ofclaim 1 wherein said tubular member comprises stainless steel.
 23. Thechromatography column of claim 1 wherein said tubular member comprisesglass.
 24. The chromatography column of claim 1 wherein said inflowregion is longer than said outflow region.
 25. The chromatography columnof claim 1 wherein said inflow region is substantially longer than saidoutflow region.
 26. A chromatography column comprising: a tubular memberhaving an inlet end, an outlet end, an inner surface, and a longitudinalaxis; a first porous member disposed within said tubular member, saidfirst porous member being spaced from said inlet end so as to define aninflow region within said tubular member and between said first porousmember and said inlet end; a second porous member disposed within saidtubular member, said second porous member being spaced from said outletend so as to define an outflow region within said tubular member andbetween said second porous member and said outlet end, said inflowregion being longer than said outflow region; and a chromatography mediadisposed within said tubular member, said chromatography media beingbounded axially between said first and second porous members; whereinsaid first porous member is in downwardly slidable contact with saidinner surface of said tubular member.
 27. The chromatography column ofclaim 26 wherein said inflow region is sized to receive a sealing headfor making a seal with said inner surface of said tubular member. 28.The chromatography column of claim 26 wherein said outflow region issized to receive a sealing head for making a seal with said innersurface of said tubular member.
 29. The chromatography column of claim26 wherein said inner surface of said tubular member is substantiallycylindrical.
 30. The chromatography column of claim 26 wherein saidinner surface of said tubular member is substantially cylindricalthroughout said inflow region.
 31. The chromatography column of claim 26wherein said inner surface of said tubular member is substantiallycylindrical throughout said outflow region.
 32. The chromatographycolumn of claim 26 wherein said tubular member further comprises a firstchamfered region near said inlet end.
 33. The chromatography column ofclaim 32 wherein said tubular member further comprises a secondchamfered region near said outlet end.
 34. The chromatography column ofclaim 26 wherein said tubular member is made of a flexible materialcapable of radial compression.
 35. The chromatography column of claim 26further comprising a first sealing head having a first elastomericsealing member for making a seal with said inner surface at said sealingregion.
 36. The chromatography column of claim 35 wherein said firstsealing head further comprises a second elastomeric sealing member formaking a seal with said inner surface at said sealing region.
 37. Thechromatography column of claim 35 further comprising a second sealinghead having a third elastomeric sealing member for making a seal withsaid inner surface at said outflow region.
 38. The chromatography columnof claim 26 wherein said tubular member comprises polyethylene.
 39. Thechromatography column of claim 26 wherein said tubular member comprisesstainless steel.
 40. The chromatography column of claim 26 wherein saidtubular member comprises glass.
 41. The chromatography column of claim26 wherein said inflow region is longer than said outflow region. 42.The chromatography column of claim 26 wherein said inflow region issubstantially longer than said outflow region.
 43. A chromatographycolumn comprising: a tubular member having an inlet end, an outlet end,an inner surface, and a longitudinal axis; a first independent porousmember disposed within said tubular member, said first porous memberbeing spaced from said inlet end so as to define an inflow region withinsaid tubular member and between said first porous member and said inletend; a second independent porous member disposed within said tubularmember, said second porous member being spaced from said outlet end soas to define an outflow region within said tubular member and betweensaid second porous member and said outlet end; and a chromatographymedia disposed within said tubular member, said chromatography mediabeing bounded axially between said first and second porous members;wherein said first porous member is in axially slidable contact, towardsaid chromatography media, with said inner surface of said tubularmember, and said second porous member is in axially slidable contact,toward said chromatography media, with said inner surface of saidtubular member.
 44. The chromatography column of claim 43 wherein saidinner surface of said tubular member is substantially cylindricalthroughout said inflow region.
 45. The chromatography column of claim 43wherein said inflow region is longer than said outflow region.
 46. Thechromatography column of claim 43 wherein said inflow region issubstantially longer than said outflow region.
 47. The chromatographycolumn of claim 43 wherein said tubular member comprises polyethylene.48. The chromatography column of claim 43 wherein said tubular membercomprises stainless steel.
 49. The chromatography column of claim 43wherein said tubular member comprises glass.
 50. A chromatography columncomprising: a tubular member having an inlet end, an inner surface, anda receiving region, said receiving region being bounded by said inletend and by an independent porous member; a chromatography media insidesaid tubular member, said chromatography media being bounded by saidporous member; wherein said porous member abuts said chromatographymedia and said first porous member is also in downwardly slidablecontact with said inner surface of said tubular member and is spacedsufficiently from said inlet end so that said receiving region is longenough to permit a sample module to be inserted completely into saidreceiving region and said receiving region is also long enough toreceive a sealing member for making a seal with said inner surface ofsaid tubular member.
 51. The chromatography column of claim 50 whereinsaid tubular member comprises polyethylene.
 52. The chromatographycolumn of claim 50 wherein said tubular member comprises stainlesssteel.
 53. The chromatography column of claim 50 wherein said tubularmember comprises glass.